Railway RRB / NTPC - MCQ Practice Questions

# Sleeper Density in Indian Railways

The sleeper density for railway tracks refers to the number of sleepers (cross-ties) required per rail length unit, expressed as $M+x$, where $M$ is the rail length in meters.

Step 1: Understanding Sleeper Density Formula

In Indian railways, the standard sleeper density formula is:

where $M$ is the rail length in meters and $c$ is a constant that varies by track type.

Step 2: Classification by Track Type

Different track categories have different density requirements:

Step 3: Main Track Standard in India

For main tracks in Indian railways (broad gauge standard), the sleeper density is standardized to provide adequate support under heavy and frequent traffic loads:

This means for a rail length of $M$ meters, approximately $M+4$ to $M+7$ sleepers are placed. For example, if $M=12.8$ meters, then 16.8 to 19.8 sleepers per rail would be used.

Step 4: Verification Against Options

**Answer: $M+4$ to $M+7$ sleepers per rail length (Option A)**

Average speed = Total distance / Total time = 450 km / 6 hours = 75 km/h

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